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TB Notes 2, 2001

Updates from the Research and Evaluation Branch

New Treatment Trial for Latent TB Infection

The Tuberculosis Trials Consortium (TBTC) has launched Study 26, an important and ambitious new Phase III clinical trial. Study 26 will evaluate the effectiveness and tolerability of 3 months of weekly rifapentine and isoniazid (INH), directly-observed, versus 9 months of daily INH, self-supervised, for the treatment of latent tuberculosis infection (LTBI) in high-risk patients. While 9 months of INH is highly effective and inexpensive, its use is limited because the long duration of therapy tends to discourage patient adherence. Owing to this key limitation, alternative shorter regimens have become a priority. However, concerns have been raised about the short-course 2-month rifampin/ pyrazinamide (2RZ) regimen because of safety and tolerability questions, drug-drug interactions, and the large pill burden.

Rifapentine (RPT) offers considerable programmatic advantages over rifampin owing to a pharmokinetic profile that allows once-weekly dosing. Furthermore, animal studies suggest that RPT/INH is at least equivalent to RZ or INH for treatment of LTBI.

Eligible study participants will be males and nonnursing, nonpregnant females 12 years of age and older. Their reason or risk factor for requiring treatment for LTBI should include one of the following: close contact with a person with culture-positive TB; documented recent PPD conversion; HIV-seropositivity with PPD ³5 mm; or pulmonary parenchymal fibrosis on chest x-ray and PPD ³5 mm. Patients will be followed for 2 years after completion of therapy for evidence of active tuberculosis. With a sample size of 8,000, this will be the largest clinical trial sponsored by the DTBE. The 24 sites of the TBTC started enrolling patients throughout the United States and Canada on June 5, 2001, but it is expected that expansion of TBTC capacity and international collaboration will be needed to strengthen enrollment.

If a regimen of once-weekly 3RPT/INH is as effective and well-tolerated as daily 9INH, 3RPT/INH would be considered a first-line regimen for the treatment of latent M. tuberculosis infection. It would be a key component to achieving the CDC goal of eliminating TB in the United States. Elsa Villarino, MD, from the Research and Evaluation Branch, DTBE, is the project officer of the study and Timothy R. Sterling, MD, from Johns Hopkins School of Medicine and the Baltimore City Health Department, is the protocol chair.

óReported by Sam (Judith) Hackman, RN,
Baltimore City Health Department
Johns Hopkins School of Medicine

Editorís note: Ms. Hackman is one of the two coordinators who are part of the Study Protocol Team for Study 26. She is the study coordinator for Johns Hopkins University; in addition, she writes and coordinates the Study 26 newsletter.


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

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